fix soil damaged by chem fertilizer?

I have a soil with very high calcium, pH, potassium, and phosphorus. The land was farmed by a hobby farmer previously. From various reports, I think the might have been a bit crazy in his farming technique. I could imagine him not bothering with a soil test, frustrated with poor yields due to high pH, and pouring on chemical fertilizer to try and fix things.

What should I do to repair any damage and fix imbalances? The pH is 7.8, the potassium is 858 ppm, the phosphorus is 80 ppm, calcium is 6300 ppm. Boron and manganese are also quite high.

There is currently bindweed growing. There does not seem to be much organic matter in the soil. If my hypothetical scenario outlined above is correct, it was probably vaporized by all the chemical N-P-K applied.

Organic matter can be lost by a variety of processes, and it is a slow process to build it back up. It's partly because soil organic matter is a 'Goldilocks' problem, all the conditions have to be "just right" to build it up to good levels. In the case of soils, "just right" means weather patterns like you find in Iowa and Illinois, where they have not just inches, but feet of black dirt. They get enough rainfall for there to be abundant foliage during the growing months, and it is cold enough in the winter to slow down the decomposition. In tropical climates, the decomposition rate is too fast and it is hard to build up soil organic matter. In colder climates, the growing season is too short to get enough biomass. In drier climates, there is not enough water to get enough biomass.

If you compare your climate in Colorado to Iowa and Illinois, the temperatures may be about the same, but the precipitation is the big difference. Your drier climate means you can't grow enough biomass to turn under to build up the soil organic matter, and the dry climate also allows for higher pH and high boron. From what you mention, the high boron is most problematic. The only real way you can get that down is to leach it out -- lots of rain or irrigation. Over this coming winter, if you can convince the local snowplows to push the snow on top of your soil, that might help a whole lot. Really pile it up and have a good sledding hill where your garden is. Then when spring comes around, start working in the organic matter. That will slowly bring down the pH as the organic matter decomposes.

Do you have a good source for biomass that you can dump on your garden? Lawn clippings? Tree trimming services?

Hello John,

How much boron causes a problem? I have 1.7 ppm.

Yes, I can get lots of organic matter. Tree crews, landscaping companies and horse stables have been dumping enormous piles of manure, leaves, and wood chips.

Fortunately, we have a moister site than most in Colorado due to irrigation ditches. That is a good idea about snow plows, but I don't think it would work here in Denver; most snows just melt off the roads, and we are on a little side dead end road that would be last on the list of plow targets (if they ever got there.)

Too bad you don't have a mall parking lot nearby, where they pile up a mountain of snow that is still sitting around weeks after everything else has melted.

That sounds like a fine value for soil boron. The areas that have problems with boron excess are dry lake beds in the west -- think Death Valley and the 20 mule team borax wagons. Boron deficiency is a problem in my part of the country (due to our 50+ inches of rain a year) and I'm still trying to figure out a good program to keep the fruit trees supplied with enough boron so I get good fruit set.

You said that you can get a ton of biomass, then try your best to cover your entire land with 6-9 inches of woodchip.
Also get a outdoor cat, never feed it only give it treats like milk of fish every so often to keep it "tame" so that it can feed on the your new vole/gopher/rodent problem

just shooting from the hip, I dont think any of the numbers you reported sound overly problematic. Lots of calcium and phosphorous are great! Your boron and potassium levels are good too. What are your numbers for sulfur and organic matter? The key to good soil mineralization is balance, not individual numbers.

We have alkaline soils in Colorado. It is not a problem. Trouble is, lots of gardening books written East of the Rockies arent used to natural alkalinity, so they dont deal with it properly. Check out The Intelligent Gardiner by Steve Solomon, he understands the pros and cons of alkaline soil, and helps you to understand how to manage natural alkalinity to your advantage. He also gives a good numerical basis for understanding mineral balance in the soil, looking at different elements in proportion to one another. I think you will find your soil is much better than you fear.

Bindweed is just a fact of life in unmanaged ground. It takes time, patience, and persistance to overcome, but it can be done. I think one key is to start small with your garden plot, so that you can maintain the upper hand over the bindweed. Many folks really struggle because they try to garden too much ground, and cant keep up with the bindweed. Start small and expand over time, so that bindweed can't keep up with you!

good luck!

Gilbert,
Check out the book "The Ideal Soil" by Michael Astera. It contains excellent info on balancing soils. website SoilMinerals.com is good place to start. Logical no nonsense info to help correct imbalances.

People from Denver write a Saturday Morning Gardening diary over at the DailyKos, if I'm allowed to say that here, I hope. Anyway, they, being from the same area, might be able to help you out. My 2 cents would be to add any organic matter you can haul in, sheet compost style, see what it does. Can't hurt, I wouldn't think. Best of luck to you! TM

Lots of good advice here. I'll throw in your Ag Extension Office too. I've found the articles on this site to be of high quality.

Soil test for toxins. If you have little money then cover with an impermeable membrane, then cover with new soil. If you have money and you want to stay where you are then remove contaminated soil and put new soil down. If you are real rich and wealthy move to a plot that is not contaminated.